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TI-2026-17603 Aliases CVE-2026-21903GHSA-h3c8-3472-7v7g

Junos OS: Subscribing to telemetry sensors at scale causes all FPCs to crash

Priority LOW 31CWE-121Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-121 and the CVSS impact.

Summary

A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authenticated with low privileges to cause a Denial-of-Service (DoS). Subscribing to telemetry sensors at scale causes all FPC connections to drop, resulting in an FPC crash and restart. The issue was not seen when YANG packages for the specific sensors were installed. This issue affects Junos OS:  * all versions before 22.4R3-S7, * 23.2 version before 23.2R2-S4, * 23.4 versions before 23.4R2.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00399 34th percentileScored 2026-11-07
Fix Fixed Junos OS (Juniper Networks): 22.4R3-S7, 23.2R2-S4, 23.4R2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
JuniperJunos OSbefore 22.4R3-S7; 23.2 to before 23.2R2-S4; 23.4 to before 23.4R222.4R3-S7, 23.2R2-S4, 23.4R2Patch availableCNA
  • Junos OS VendorJuniper Affected before 22.4R3-S7; 23.2 to before 23.2R2-S4; 23.4 to before 23.4R2 Fixed in 22.4R3-S7, 23.2R2-S4, 23.4R2 Patch available CNA

CPE configurations NVD · 27

CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*before 22.4VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:-:*:*:*:*:*:*22.4VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r1:*:*:*:*:*:*22.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r1-s1:*:*:*:*:*:*22.4 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r1-s2:*:*:*:*:*:*22.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r2:*:*:*:*:*:*22.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r2-s1:*:*:*:*:*:*22.4 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r2-s2:*:*:*:*:*:*22.4 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r3:*:*:*:*:*:*22.4 r3VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r3-s1:*:*:*:*:*:*22.4 r3-s1VulnerableJuniper
  • cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* Versions before 22.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:-:*:*:*:*:*:* Versions 22.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r1:*:*:*:*:*:* Versions 22.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r1-s1:*:*:*:*:*:* Versions 22.4 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r1-s2:*:*:*:*:*:* Versions 22.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r2:*:*:*:*:*:* Versions 22.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r2-s1:*:*:*:*:*:* Versions 22.4 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r2-s2:*:*:*:*:*:* Versions 22.4 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r3:*:*:*:*:*:* Versions 22.4 r3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r3-s1:*:*:*:*:*:* Versions 22.4 r3-s1 Vulnerable ·Juniper
Show 17 more CPE
CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos:22.4:r3-s2:*:*:*:*:*:*22.4 r3-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r3-s3:*:*:*:*:*:*22.4 r3-s3VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r3-s4:*:*:*:*:*:*22.4 r3-s4VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r3-s5:*:*:*:*:*:*22.4 r3-s5VulnerableJuniper
cpe:2.3:o:juniper:junos:22.4:r3-s6:*:*:*:*:*:*22.4 r3-s6VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:-:*:*:*:*:*:*23.2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:*23.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:*23.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:*23.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2:*:*:*:*:*:*23.2 r2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s1:*:*:*:*:*:*23.2 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s2:*:*:*:*:*:*23.2 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s3:*:*:*:*:*:*23.2 r2-s3VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:*23.4VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:*23.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:*23.4 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r1-s2:*:*:*:*:*:*23.4 r1-s2VulnerableJuniper
  • cpe:2.3:o:juniper:junos:22.4:r3-s2:*:*:*:*:*:* Versions 22.4 r3-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r3-s3:*:*:*:*:*:* Versions 22.4 r3-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r3-s4:*:*:*:*:*:* Versions 22.4 r3-s4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r3-s5:*:*:*:*:*:* Versions 22.4 r3-s5 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:22.4:r3-s6:*:*:*:*:*:* Versions 22.4 r3-s6 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:-:*:*:*:*:*:* Versions 23.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:* Versions 23.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:* Versions 23.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:* Versions 23.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2:*:*:*:*:*:* Versions 23.2 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s1:*:*:*:*:*:* Versions 23.2 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s2:*:*:*:*:*:* Versions 23.2 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s3:*:*:*:*:*:* Versions 23.2 r2-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:* Versions 23.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:* Versions 23.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:* Versions 23.4 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r1-s2:*:*:*:*:*:* Versions 23.4 r1-s2 Vulnerable ·Juniper

Remediation

  • Fix · CNA Junos OS (Juniper Networks) Fixed in 22.4R3-S7, 23.2R2-S4, 23.4R2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-21903
  2. 2026-10-03 Alias added: GHSA-h3c8-3472-7v7g

References

Advisory 2

  • TI-2023-18638 Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to… KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-01585 Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) services KEVCVSS 3.1CRITICAL 9.8
  • TI-2015-04610 Assertion failure in ISC BIND named via TKEY queries KEVCVSS 3.1HIGH 7.5
  • TI-2025-15550 Junos OS: An local attacker with shell access can execute arbitrary code KEVCVSS 4.0MEDIUM 6.7
  • TI-2023-18644 Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload and download arbitrary files KEVCVSS 3.1MEDIUM 5.3
  • TI-2023-18640 Junos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary files KEVCVSS 3.1MEDIUM 5.3
See all 792 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences